Rotary switch



Sept. 3, 1946a G. H. EFB 2,405,818

ROTARY SWITCH Filed May 7, 1.945 2 sheets-sheet, 1

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ROTARY SWITCH Filed May "i, 1945 2 sheets-sheet 2 v x INVENTOR.

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, BY v ATToRM/FY Patented Sept. 3, 194:6

UNITED STATES PATENT OFFICE ROTA-RY SWITCH George H. Erb, South Orange,N. J., assigner to` Federal Telephone and Radio Corporation, Newark, N.J., a corporationy ofDelaware Application May 7, 194.3, Serial No.485,969

1 Claim'. 1

The present invention relates to electrical switches and moreparticularly to a multi-position switch having an indexing mechanism in=corporated therewith.

Although indexing vdevices for switches are well known in the art, it isone purpose of the present invention to provide an improved assemblyinwhich the switch contacts and the indexing mechanism are enclosed as aunit within a housing of relatively smallV size.

It is a further object of the invention to provide an indexing mechanismthat will have a positive action but at the same time can be actuatedwith a minimum of effort.

It is another object of the invention to provide an indexing mechanismthat will maintain the switch contacts in the position selectedregardless of vibration or shocks that may be applied to thev switchhousing or to the control structure.

The invention still further contemplates an indexing device thatincludes interchangeable parts, so that by a proper selection of suchparts the indexing mechanism can be made to respond to operating forcesof any desired magnitude.

Other objects and advantages will be apparent from the followingdescription of a preferred form of ther invention and from the drawings,in which:

Fig. 1 is a sectional View of a switch assembly in accordance with thepresent invention;

Fig. 2 is a view along 2 2 of Fig. 1;

Fig. 3 is a View along 3 3. of Fig. 1, showing the inner rotor assembly;

Fig. 4 isy a view along il-t of Fig- 1, showing the outer contactassembly;

Fig. 5 is a sectional View of the tube cradle of Fig. l.

In Fig. 1 is shown a rotatable shaft 6 on which is mounted an insulatingmember Ztl supporting a plurality of inner switch contacts 30. Aplurality of rivets 32 respectively position inner contacts 30 oninsulating member 20, this construction being also shown in Fig. 3. Eachof these inner contacts 30 comprises a pair of flexible spring elementsdisposed in substantially parallel relationship and having ears on theouter corners thereof to facilitate engagement with stationary outercontacts I5, as will hereinafter be described.

A ring-shaped insulating member I2 (see also Fig. 4) supports andpositions a plurality of outer stationary contacts I6, this ring-shapedinsulating member I2 forming a part of the assembly housing, as can beseen from Fig. 1. The outer contacts I6 are spaced apart by a raisedcircular portion I3 of member I2, and a plurality of rivets I8respectively connect these outer contacts It with exterior terminals I4.Another raised circular portion I5 of insulating member I2 spaces andretains in position outer terminals I4.

On one side of insulating. member 20 is a raised surface portion 2|shaped so as not to interfere with the positioning of contacts B by pins32` (see Fig. 3). A slot in this portion 2l receives a pin 2'2 whichextends through shaft 5, and is securely positioned thereby. Thus arotation of shaft t will correspondingly rotate insulating member 2t! aswell as associated inner contacts 30.

A front cover i0 for the assembly fits against insulating member i2 andhas a bushing S enclosing shaft 6. This bushinfr may be externallythreaded to permit connection of the switch assembly to a suitablemounting. Between bushing 8` and the raised surface 2'I of insulatingmember 2,5 are a washer 28 and a pair of spacers 24 and 2t.

rI'he extremity of shaft E is formed' with a cup* shaped opening asshown in Fig; l, and a tube cradle 313i is insertably positioned in thisopening. A'v tubular extending portion 35 of shaft 6 is formed' axiallythereof and passes through an opening 3l in tube cradle 34 (see Fig. 5).The extending portion is peened over to securely position on shaft 6 thecradle 3d and the insulating member 20'.

A spring retaining tube 4B is securely attached to tube cradle (iii bymeans such as soldering, the tube cradle being shaped to receive thetube 40 as shown in Fig. 5. A spring 'l2 is compressibly positioned intube 40, and a pair of spring guides 44 and 45 at the ends of spring 4i!respectively Contact an upper ball bearing 4S and a lower ball bearing43. A rear cover 38 adjoins insulating member i2 and with this memberand front cover lil form a compact housing unit for the switch andindexing assembly.

Rear cover 38 is constructed as best shown in Fig. 2. A recess 41 on theinner surface thereof is designed to receive the spring retaining tube40. In the upper portion of recess 41 are formed three niches 49, and 5Ishaped to receive the ball bearing 46 which is partially enclosed withinspring retaining tube 40. Ball bearing 48 rides along the smooth lowersurface of recess 4l as shown. Threaded openings 52 on cover 38,insulating member I2, and the front cover I0, receive screws (not shown)which when tightened tend to form a relatively dust-proof enclosure forthe assembly,

From Figs. 1 and 3 it can be seen that a rotation of the shaft E willrotate the insulating member 2i) and the inner contacts 3i). Thesecontacts 30 will then selectively bridge or connect the outer contactsi6 (Fig. 4) The present disclosure is not limited to any combination orarrangement of circuits, but it will be obvious that a large number ofswitching variations within the scope of the invention can be obtainedby altering the spacing of the outer contacts IB and/or the design ofthe inner contacts 30.

As will be seen from Fig. l, each spring contact 30 is designed as apair of flexible sections disposed iace to face so that an outer contactIt may pass between these sections upon rotation of shaft thisconstruction insuring an electrical connection between the inner andouter contact elements. The ears on the corners of the inner contacts 3@are to guide the outer contacts i6 in passing between the sections ofsuch inner contacts.

ssume now that the indexing mechanism is in the position shown in Figs.1 and 2, that is, with the ball bearing it of spring retaining tube blt]in the central niche D in recess 4l of rear cover Due to the tension ofspring 512, spring guide iii exerts pressure on bearing 'iE to holdbearing it in niche Sii, thus positioning tube 11E! in place in recessLil. The resultant pressure of spring in the opposite direction isexerted against spring guide 'l5 and ball bearing lill, but sincebearing i8 rides along the smooth lower surface of recess no oppositionis offered by bearing d8 to a rotation of shaft ii.

When it is desired to actuate the shaft 6 to another of its contactpositions, the angular movement of tube i@ will force ball bearing 455against the sloping surface of niche 55, and sufficient pressure willresult in a depressing of ball bearing Lie into tube do for a suflicientdistance to permit the upper surface of bearing i6 to clear the sharpedge between niches 5i] and El (or 43, depending on the direction ofrotation of shaft f5). As soon as the bearing @il enters niche 5| itwill center the tube 40 in such niche due to the tension of spring 52.Thus a positive indexing operation results, and since the spring i2permits the tube to have a limited movement transversely of shaft f5without the ball bearing 46 being displaced from the niches 4S, 50 and5I,

ie disclosed structure will resist a shock or vibration applied to theshaft or housing in a direction perpendicular to the axis of the shaftand having a tendencyto disturb the selected relationship of the switchcontacts I6, 30. Since it can also be seen from Fig. 1 that the springretaining tube 4i) does not directly contact the inner surface of rearcover 38, any vibration or other shock applied longitudinally along theaxis of the shaft will be taken up by the spring contacts 353 and i6without disturbing their circuit relationship. since the applied forceis at right angles to their direction of rotation.

It should be noted that due to the relatively short radius of theindexing mechanism, little operating force need be applied to the shaftB to actuate the switch assembly. Furthermore it will be apparent thatby removing the rear cover 38 the ball bearings 46, 48, the springguides 44, 125, and the spring 42 may be quickly removed from the tube42. By selecting a spring having a different degree of resiliency, theswitch assembly can be made to respond to any desired operating force,this change being effected without disturbing in any way the switchcontacts 30, I6, and without the necessity of breaking the circuit whenthe spring replacement is made.

While I have described above the principles or my invention inconnection with speciiic apparatus, it is to be clearly understood thatthis description is made only by way of example and not as a limitationon the scope of my invention as set forth in the objects of my inventionand the accompanying claim.

I claim:

In a. compact rotary switch and indexing mechanism, a housing having asubstantially dustproof recess therein, said recess comprising twoportions, one portion being substantially cylindrical and containing aplurality of radially projecting contacts, and the other portion beingsubstantially the shape of two opposing sectors wherein the arcuatesurface of one sector is smooth and the surface of the other sectorcontains a plurality of spaced-apart axial grooves, a rotatable sl'iaitsupported by said housing coaxial with said recess, one or moreconducting elements carried by said shaft for bridging adjacent radiallyprojecting contacts in said cylindrical portion of said recess, andindexing mechanism within said other dual-sector-shaped recess portioncomprising a transverse bearing holder mounted on the said shaft and apair of bearings, one of said bearings directly engaging said axiallygrooved arcuate surface, and the other of said bearings directlyengaging 'said smooth arcuate surface.

GEORGE H. ERB.

